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Multi-granularity sequence generation for hierarchical image classification

Computational Visual Media 2024年第2期10卷 243-260页

作者： Xinda liu lili Wang State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China Peng Cheng Laboratory Shengzhen 518000China

Hierarchical multi-granularity image classification is a challenging task that aims to tag each given image with multiple granularity labels simultaneously.Existing methods tend to overlook that different image regions contribute differently to label prediction at different granularities,and also insufficiently consider relationships between the hierarchical multi-granularity labels.We introduce a sequence-to-sequence mechanism to overcome these two problems and propose a multi-granularity sequence generation(MGSG)approach for the hierarchical multi-granularity image classification task.Specifically,we introduce a transformer architecture to encode the image into visual representation sequences.Next,we traverse the taxonomic tree and organize the multi-granularity labels into sequences,and vectorize them and add positional information.The proposed multi-granularity sequence generation method builds a decoder that takes visual representation sequences and semantic label embedding as inputs,and outputs the predicted multi-granularity label sequence.The decoder models dependencies and correlations between multi-granularity labels through a masked multi-head self-attention mechanism,and relates visual information to the semantic label information through a crossmodality attention mechanism.In this way,the proposed method preserves the relationships between labels at different granularity levels and takes into account the influence of different image regions on labels with different granularities.Evaluations on six public benchmarks qualitatively and quantitatively demonstrate the advantages of the proposed method.Our project is available at https://***/liuxindazz/mgs.

关键词： hierarchical multi-granularity classification vision and text transformer sequence generation fine-grained image recognition cross-modality attenti

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Essential role of the iron-sulfur cluster binding domain of the primase regulatory subunit Pri2 in DNA replication initiation

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Protein & Cell 2015年第3期6卷 194-210页

作者： Lili Liu Mingxia Huang Department of Pharmacology and Chemical Biology University of Pittsburgh School of Medicine Pittsburgh PA 15213 USA Department of Biochemistry and Molecular Genetics University of Colorado School of Medicine Aurora CO 80045 USA

DNA primase catalyzes de novo synthesis of a short RNA primer that is further extended by replicative DNA polymerases during initiation of DNA replication. The eukaryotic primase is a heterodimeric enzyme comprising a catalytic subunit Pril and a regulatory subunit Pri2. Pri2 is responsible for facilitating optimal RNA primer synthesis by Pril and mediating interaction between Pril and DNA polymerase o for transition from RNA synthesis to DNA elongation. All eukaryotic Pri2 proteins contain a conserved C-terminal iron-sulfur （Fe-S） cluster-binding domain that is critical for primase catalytic activity in vitro. Here we show that mutations at conserved cysteine ligands for the Pri2 Fe-S cluster markedly decrease the protein stability, thereby causing S phase arrest at the restrictive temperature. Furthermore, Pri2 cysteine mutants are defective in loading of the entire DNA pol α-primase complex onto early replication origins resulting in defective initiation. Importantly, assembly of the Fe-S cluster in Pri2 is impaired not only by mutations at the conserved cysteine ligands but also by increased oxidative stress in the sodlA mutant lacking the Cu/Zn superoxide dismutase. Together these findings highlight the critical role of Pri2＇s Fe-S cluster domain in replication initiation in vivo and suggest a molecular basis for how DNA replication can be influenced by changes in cellular redox state.

关键词： pdmase Pri2 iron-sulfur cluster,replication initiation

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Global stability of an age-structured SVEIR epidemic model with waning immunity, latency and relapse

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International Journal of Biomathematics 2017年第3期10卷 151-178页

作者： Lili Liu Xianning liu Complex Systems Research Center Shanxi University Taiyuan Shan'xi 030006 P. R. China Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education) School of Mathematics and Statistics Southwest University Chongqing 400715 P. R. China

The global dynamics of an SVEIR epidemic model with age-dependent waning immunity, latency and relapse are studied. Sharp threshold properties for global asymptotic stability of both disease-free equilibrium and endemic equilibrium are given. The asymptotic smoothness, uniform persistence and the existence of interior global attractor of the semi-flow generated by a family of solutions of the system are also addressed. Furthermore, some related strategies for controlling the spread of diseases are discussed. [ABSTRACT FROM AUTHOR]

关键词： age-dependent latency age-dependent relapse global stability SVEIR epidemic model waning immunity

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Foveated rendering:A state-of-the-art survey

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Computational Visual Media 2023年第2期9卷 195-228页

作者： lili Wang Xuehuai Shi Yi liu State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100000China Peng Cheng Laboratory Shengzhen 518000China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100000China.

Recently,virtual reality(VR)technology has been widely used in medical,military,manufacturing,entertainment,and other fields.These applications must simulate different complex material surfaces,various dynamic objects,and complex physical phenomena,increasing the complexity of VR scenes.Current computing devices cannot efficiently render these complex scenes in real time,and delayed rendering makes the content observed by the user inconsistent with the user’s interaction,causing discomfort.Foveated rendering is a promising technique that can accelerate rendering.It takes advantage of human eyes’inherent features and renders different regions with different qualities without sacrificing perceived visual quality.Foveated rendering research has a history of 31 years and is mainly focused on solving the following three problems.The first is to apply perceptual models of the human visual system into foveated rendering.The second is to render the image with different qualities according to foveation principles.The third is to integrate foveated rendering into existing rendering paradigms to improve rendering performance.In this survey,we review foveated rendering research from 1990 to 2021.We first revisit the visual perceptual models related to foveated rendering.Subsequently,we propose a new foveated rendering taxonomy and then classify and review the research on this basis.Finally,we discuss potential opportunities and open questions in the foveated rendering field.We anticipate that this survey will provide new researchers with a high-level overview of the state-of-the-art in this field,furnish experts with up-to-date information,and offer ideas alongside a framework to VR display software and hardware designers and engineers.

关键词： foveated rendering virtual reality(VR) real-time rendering

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Research progress on the design of electrolyte additives and their functions for zinc-ion batteries

Materials Futures

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Materials Futures 2024年第1期3卷 31-62页

作者： Yuxin Cui Ruixin Zhang Sinian Yang Lili Liu Shimou Chen 1 College of Chemistry and Materials Engineering Beijing Technology and Business UniversityBeijing 100048People’s Republic of China State Key Laboratory of Chemical Resource Engineering Beijing Key Laboratory of Electrochemical Process and Technology of MaterialsBeijing University of Chemical TechnologyBeijing 10029People’s Republic of China

In recent years,zinc-ion batteries(ZIBs)have been considered one of the most promising candidates for next-generation electrochemical energy storage systems due to their advantages of high safety,high specific capacity and high economic efficiency.As an indispensable component,the electrolyte has the function of connecting the cathode and the anode,and plays a key role in the performance of the battery.Different types of electrolytes have different effects on the performance of ZIBs,and the use of additives has further developed the research on modified electrolytes,thus effectively solving many serious problems faced by ZIBs.Therefore,to further explore the improvement of ZIBs by electrolyte engineering,it is necessary to summarize the current status of the design of various electrolyte additives,as well as their functions and mechanism in ZIBs.This paper analyzes the challenges faced by different electrolytes,reviews the different solutions of additives to solve battery problems in liquid electrolytes and solid electrolytes,and finally makes suggestions for the development of modified ZIB electrolytes.It is hoped that the review and strategies proposed in this paper will facilitate development of new electrolyte additives for ZIBs.

关键词： zinc-ion batteries additives liquid electrolytes solid electrolytes interface

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Low-dimensional perovskite modified 3D structures for higher-performance solar cells

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Journal of Energy Chemistry 2023年第6期81卷 389-403,I0009页

作者： lili Gao Ping Hu Shengzhong(Frank)liu College of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi'an 710055ShaanxiChina Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian 116023LiaoningChina School of Materials Science and Engineering Shaanxi Normal UniversityXi’an 710119ShaanxiChina

For solution prepared perovskite solar cells,metal halide perovskite materials with low-dimensional(LD)are flexibly employed in 3D perovskite solar cells to promote efficiency and long-term stability.In this review,the various structures,properties,and applications of LD perovskites are firstly summarized and discussed.To take advantage of LD materials,LD perovskites are introduced in the 3D bulk and/or the interface between the perovskite thin film and the carrier transporting layer to passivate the gain boundary defects while providing the stability advantage of LD materials.Therefore,the preparation methods and crystallization control of the LD perovskite layers are discussed in depth.Then,the combined devices using both LD and 3D components are reviewed on the basis of device design,cell structure,interface charge transfer,energy lever alignment,and synergistic improvement of both efficiency and stability.Finally,the challenges and expectations are speculated for further development of perovskite solar cells.

关键词： Low-dimensional Structure Perovskite solar cell Efficiency Service stability

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C2-phenyl-substituted benzimidazolium-based covalent organic framework as efficient catalyst for CO_(2) conversion without solvents,metals,and cocatalysts

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Science China Chemistry 2024年第2期67卷 551-557页

作者： Zhenzhen Wu Jing Wang Lili Liu Shang Guo Juan Li Xianming Zhang Shanxi Institute for Functional Food Shanxi Agricultural UniversityTaiyuan030031China Institute of Crystalline Materials Shanxi UniversityTaiyuan030006China Key Laboratory of Interface Science and Engineering in Advanced Materials College of ChemistryTaiyuan University of TechnologyTaiyuan030024China

Covalent organic frameworks(COFs) are a potential platform for carbon dioxide(CO_(2)) conversion owing to their periodic permanent porosity,adjustable structure,and chemical stability.For good catalytic performance in CO_(2) conversion,collaborative multifunctions should be strategically integrated into the catalytic system design and construction.In this study,a four-in-one high-efficiency catalyst was synthesized and tested for CO_(2) cycloaddition to form cyclic carbonate.The obtained Tp-MPB-BrCOF had a high nitrogen content,which enhanced its CO_(2) affinity through substantial Lewis acid-base or dipole-quadrupole interactions;moreover,the acid(protons transferring from oxygen(–OH) to nitrogen(–NH)),hydrogen bond donor(hydroxyl group),and Br-(nucleophile group) served as three active sites,further improving the catalyst activity.These results provide a basis for designing efficient and stable CO_(2)-conversion catalysts.

关键词： covalent organic framework C2-phenyl-substituted benzimidazolium CO_(2)conversion four-in-one catalyst

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Upconversion fluorescence modulation of CaTiO_(3):Yb^(3+)/Er^(3+)nanocubes via Zn^(2+)introduction

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Optoelectronics Letters 2022年第3期18卷 129-134页

作者： MU Jiajia liu Jinyu GAO lili School of Science Beihua UniversityJilin 132013China

To investigate the effect of Zn^(2+)ions on the luminescence properties of rare earth(RE)doped calcium titanate materials,CaTiO_(3):Yb^(3+)/Er^(3+)/Zn^(2+)nanocubes with uniform size were prepared by solvothermal method in this paper.They were respectively characterized by X-ray diffractometer(XRD),scanning electron microscope(SEM),photoluminescence(PL)spectroscopy and their fluorescence lifetimes.The results show that the average size of the nanocubes is about 550 nm×650 nm×850 nm with good upconversion luminescence(UCL)properties.Under 980 nm laser excitation,the effects of the ratio between activator Er^(3+)and sensitizer Yb^(3+)and Zn^(2+)doping on the upconversion fluorescence properties were investigated,and the optimal ion ratio was obtained.The results of steady-state spectra show that the strongest fluorescence intensity of CaTiO_(3):Yb^(3+)/Er^(3+)was obtained with the addition of 10 mol%Zn^(2+)at a Yb^(3+)/Er^(3+)molar doping ratio of 3:0.3,which was attributed to the crystal field asymmetry generated by the introduction of Zn^(2+)ions.The energy transfer and upconversion mechanism between Yb^(3+)and Er^(3+)ions in CaTiO_(3) nanocubes were investigated by analyzing the upconversion fluorescence kinetics.

关键词： properties kinetics doping

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Biomimetic three-dimensional multilevel nanoarray electrodes with superaerophobicity as efficient bifunctional catalysts for electrochemical water splitting

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Nano Research 2023年第5期16卷 6584-6592页

作者： Dongdong Wang Yue liu Lili Liu Dongfang Shan Guixin Shen Shanlong Peng Heng Zhang Xindong Wang State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing 100083China Energy Storage Science and Engineering School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing 100083China

The design and preparation of cost-effective and durable catalysts for electrochemical water splitting are significant for the development and application of hydrogen production.Herein,inspired by the underwater superaerophobicity of fish scales,a three-dimensional multilevel nanoarray electrode with superaerophobicity was designed and fabricated by the hydrothermal method to solve the bubble shielding effect in electrochemical reactions.Benefiting from the high specific surface area,superaerophobic properties,Al doping,the Al-CoS_(2)nanosheets(NSs)/nickel foam(NF)-30 exhibits outstanding electrocatalytic activity and superior durability for electrochemical water splitting in 1 M KOH.Significantly,the Al-CoS_(2)NSs/NF-30 only required extremely low overpotential of 176 mV for oxygen evolution reaction(OER)to reach a current density of 10 mA·cm^(-2).Al-CoS_(2)NSs/NF-30 was employed as bifunctional electrode for electrochemical water splitting with a cell voltage of 1.58 V at 10 mA·cm^(-2).Meanwhile,Al-CoS_(2) NSs/NF-30 exhibited excellent durability(250 h@10 mA·cm^(-2)and 50 h@100 mA·cm^(-2)).The cobalt-based catalyst(Al-CoS_(2) NSs/NF-30)with superaerophobicity exhibits excellent performance in activity and durability,therefore is a promising electrochemical water splitting catalyst.

关键词： oxygen evolution reaction biomimetic structure superaerophobicity hydrogen evolution reaction

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Role of iron-based catalysts in reducing NO_(x) emissions from coal combustion

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中国化学工程学报:英文版 2023年第7期59卷 1-8页

作者： Yuehua liu lili Chen Shoujun liu Song Yang Ju Shangguan State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan 030024China Shanxi Engineering Center of Civil Clean Fuel Taiyuan University of TechnologyTaiyuan 030024China College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China

Nitrogen oxide(NO_(x))pollutants emitted from coal combustion are attracting growing public concern.While the traditional technologies of reducing NO_(x) were mainly focused on terminal treatment,and the research on source treatment is limited.This paper proposes a new coal combustion strategy that significantly reduces NO_(x) emissions during coal combustion.This strategy has two important advantages in reducing NO_(x) emissions.First,by introducing iron-based catalyst at the source,which will catalyze the conversion of coke nitrogen to volatile nitrogen during the pyrolysis process,thereby greatly reducing the coke nitrogen content.The second is de-NO_(x) process by a redox reaction between NO_(x) and reducing agents(coke,HCN,NH_(3),etc.)that occurred during coke combustion.Compared to direct combustion of coal,coke prepared by adding iron-based catalyst has 46.1% reduction in NO_(x) emissions.To determine the effect of iron-based additives on de-NO_(x) performance,demineralized coal(de-coal)was prepared to eliminate the effect of iron-based minerals in coal ash.The effects of iron compounds,additive dosages,and combustion temperatures on de-NO_(x) efficiency are systematically studied.The results revealed that the NO_(x) emission of the coke generated by pyrolysis of de-coal loaded with 3%(mass)Fe_(2)O_(3) decreases to 27.3% at combustion temperature of 900℃.Two main reasons for lower NO_(x) emissions were deduced:(1)During the catalytic coal pyrolysis stage,the nitrogen content in the coke decreases with the release of volatile nitrogen.(2)Part of the NO_(x) emitted during the coke combustion was converted into N_(2) for the catalytic effect of the Fe-based catalysts.It is of great practical value and scientific significance to the comprehensive treatment and the clean utilization process of coal.

关键词： NO_(x) Coal combustion Coal pyrolysis Fe2O3 catalyst

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